[PATCH 18/18] [DO NOT MERGE] Makefile: enable switch/case fallthrough warnings

[Tom Rini]

On Thu, Mar 27, 2025 at 03:33:13PM +0000, Andre Przywara wrote:

> =================================================================
> This does not fully work yet, there is at least the libbz2 code
> left to be handled. But this patch helps to let CI find more
> places where we need annotations.
> =================================================================
> 
> C's implicit fallthrough behaviour in switch/case statements can lead to
> subtle bugs. Quite some while ago many compilers introduced warnings in
> those cases, requiring intentional fallthrough's to be annotated.
> 
> So far we were not enabling that compiler option, so many ambiguities
> and some bugs in the code went unnoticed.
> 
> With all places that produced warnings fixed or annotated now, we can
> add this compiler option to the build flags, to find new ambiguities
> early, before the code gets merged.
> 
> Signed-off-by: Andre Przywara <andre.przywara at arm.com>
> ---
>  Makefile | 1 +
>  1 file changed, 1 insertion(+)

For the record, once this is ready to be merged I would like to see us
borrow the CC_IMPLICIT_FALLTHROUGH logic from the linux kernel (which
gets the best flags for gcc or clang) instead, but yes, default to
enabling the check.

-- 
Tom
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